Exchange 2013 mailbox migration fails with no error

Following on from some recent database corruptions and repairs, I decided it was a good idea to create a new Exchange database and move all my mailboxes across to it.

This worked fine for all but one, which also happened to be my own.

Every time I would do the migration, it would all appear to be fine, but then it would finish as Completed, with no errors, but showing in the EAC as Synced and Finalized mailboxes: 0 of 0

I tried again and watched more closely and noticed it the extended “show details” that it was reporting an issue with the not being able to connect to the System Attendant mailbox. Various searches led me to articles about if the arbitration mailbox is accidentaly deleted how to re-create it etc, but this was not the problem.

Digging a bit further I noticed a mention of the mailbox being Quarantined.

SOLUTION

While not *exactly* the same situation, it was close enough and seemed worth checking. The “Get-Mailbox” command it mentions didn’t work for me (no idea why, mystery for another day) but as there was only one GUID in the registry that was quarantined it didn’t really matter